A Warrantless Arrest, also known as “citizen’s arrest,” is lawful under three circumstances:
1) In Flagrante Delicto – When, in the presence of the policeman, the person to be arrested has committed, is actually committing, or is attempting to commit an offense.
2) Hot Pursuit – When an offense has just been committed, and he has probable cause to believe, based on personal knowledge of facts or circumstances, that the person to be arrested has committed it.
3) When the person to be arrested is a prisoner who has escaped from a Penal Establishment.
Section 5, Rule 113 of the Rules of Court